Postlingual single-sided deafness (SSD) is a type of hearing impairment with normal hearing in one ear and severely impaired hearing in the other ear. The condition induces multiple changes of neural plasticity in central auditory pathways. One manifestation reflects an increased common activation of the contralateral and ipsilateral pathways after stimulation of the normal hearing ear which is correlated with an increased activity between the contralateral and ipsilateral hemispheres. As the left and right hemisphere are specialized for different auditory tasks, the proposed study aims at demonstrating different consequences of right or left-sided deafness for the affected individual. Furthermore, the question should be answered if auditory deficits and plastic changes can be partially reversed by cochlear implantation of the deaf ear. It is assumed that some changes induced by SSD can be detected only by reversal through a cochlear implant.